Fall is approaching and everyone is looking forward to fall colors. The most common bright fall colored tree is the Red Maple. There are a seemingly endless number of maple cultivars that are propagated for a variety of landscape attributes, of which fall color is a dominant factor. However, many of these cultivars locally available are native to regions ranging from Tennessee to Ohio. These maples generally come from plant hardiness zones 4 to 7 while most of Baldwin and Mobile counties is in zone 8b (hardiness zones range from zone 2 near the Canadian border to zone 10 in south Florida).
While there are red maples native to south Alabama, they are not commonly propagated for retail, instead cultivars like ‘Autumn Flame’ are more common. The drastic climatic differences between Ohio’s zone 4 and the Gulf Coast’s zone 8b make many red maple cultivars a poor choice. Trees planted out of their hardiness zones often become stressed due to our extreme heat and humidity and are more susceptible to a variety of pests and diseases.
Seldom do these red maple cultivars live more than a few years under ideal conditions on the Gulf Coast and most decline and die within three years. Treatment of pests like borers is difficult and only a temporary solution as the major predetermining factor is climate. Good urban forest management starts with proper tree selection for the right climatic zone, light exposure, soil type and available growing space.
As a result, it is no secret that the bright reds, oranges and yellows of a picture perfect fall in Maine are difficult to find on Alabama’s Gulf Coast. There are many factors that contribute to this reduced vibrancy in fall colors. The foremost factor is the absence of the climate needed to produce fall colors. Fall colors depend on warm days followed by a long succession of cool crisp, but not freezing, nights to produce the biological responses necessary to allow the pigments to be produced.
For most of the year, the green pigment chlorophyll needed for photosynthesis overpowers the more subtle yellow, orange and red pigments. The shortening fall days slowly reduce the overpowering green chlorophyll while simultaneously the prescribed warm days allow trees to produce sugars that the cool nights trap in the leaves. These trapped sugars force the trees into a biological process that converts these sugars into bright yellow, orange and red pigments we call fall color.
On the Gulf Coast, the more temperate and humid nights and the lack of a long succession of cool evenings dampen this process into more subtle variations. Another factor reducing our fall colors are the tree species available to us. The maples, oaks, hickories and other northern species famous for producing fall color are generally not found on the gulf coast. Finally, the genetic variability between northern and southern trees of the same species also results in reduced fall color.
Regardless of the fact that our fall colors are more subdued, there are some good tree selections that can add color to our yards. Black Gum and Sweet Gum are two native trees that will provide excellent, if short lived, fall color. Their leaves will generally turn a red to purple color, however, both of these trees will drop their leaves early in the fall. Ginko is a beautiful choice if you hope to see a vibrant yellow tree. The leaves will persist longer and have a unique tendency to drop, almost at once, leaving a beautiful carpet of yellow leaves beneath their boughs.
For some of the brightest reds in our area try planting either a shining sumac, sourwood or a Chinese pistache. These trees develop deep reds, however, sourwoods tend to lack uniformity with colors ranging from browns to reds, especially for trees grown in full sun. Shining sumac, on the other hand, will produce some of the most vibrant colors in our area.
The two maples to try in our area are the Florida sugar maple, which will have a more subdued yellow to brownish orange color and the Japanese maple, which can have a wide variety of highly vibrant colors ranging from purples to glowing reds. In the chart below please see a complete list of tree selections for fall color in Mobile and Baldwin counties. Note that I have broken these down by both their size and desired light exposure as these will be important factors for their future health and survival.
|Species||Latin Name||Fall Color||Tree Size||Light Exposure|
|Black Gum||Nyssa sylvatica||Red||Large||Full Sun|
|Sweet Gum||Liquidambar styracifua||Purple||Large||Full Sun|
|Florida Sugar Maple||Acer barbatum||Yellow||Large||Full Sun|
|Ginkgo||Ginkgo biloba||Yellow||Large||Full Sun|
|Chinese Pistache||Pistacia chinensis||Red||Medium||Full Sun|
|Sourwood||Oxydendrom arboreum||Red||Medium||Partial Sun|
|Sassafras||Sassafras albidum||Orange||Medium||Partial Sun|
|Japanese Maple||Acer palmatum||Red||Small||Partial Sun|
|Downy Serviceberry||Amelanchier arborea||Red||Small||Partial Sun|
|Shining Sumac||Rhus copallina||Red||Small||Full Sun|